Four soil color charts compared in CIELAB color space

AIC 2004 Color and Paints, Interim Meeting of the International Color Association, Proceedingsand 5.36 CIELAB units in JAPAN2001 to 7.38 and 4.65, respectively, in JAPAN1970. Thisindicates a reduction of lightness distance by 18% and chroma distance by 13%.Although we do not know the specific causes, color fading in American used charts wasless pronounced. The average values in USA2000 were 9.90 for ∆L* and 5.86 for ∆C*,whereas the average values in USA1975 were 9.17 for ∆L* and 5.54 for ∆C*. A reduction ofonly 0.73 units (7%) for ∆L*, and 0.32 units (5%) for ∆C* occurred in USA1975.4. CONCLUSIONSThis study shows that the steps between color chips of standard soil color charts havedifferent size depending on their manufacturer and degree of use. For new charts, averagelightness and chroma distances between nearest neighboring chips in American charts aregreater than in Japanese charts by 0.92 and 0.50 CIELAB units, respectively. Comparing theaverage step of old and new charts, lower hue (0.80 to 0.24 CIELAB units), lightness (1.60 to0.73 CIELAB units), and chroma (0.71 to 0.31 CIELAB units) differences were found.We believe that the original quality of printing and the color fading over time lead torelevant color changes in standard soil color charts.ACKNOWLEDGMENTSResearch Projects CGL2004-02282/BTE and FIS2004-05537, Ministerio de Educación yCiencia (Spain) and FEDER. Acción Coordinada BOJA N° 17 de 27.01.2004.REFERENCESBerns, R. S. 2000. Billmeyer and Saltzman’s Principles of color technology. New York: John Wileyand Sons.Bigham, J. M., and E. J. Ciolkosz. 1993. Soil color. Madison: Soil Science Society of America.CIE. 1986. Colorimetry, Publication 15.2. Vienna: Commission Internationale de l’Éclairage.Dobos, R. R., E. J. Ciolkosz, and W. J. Waltman. 1990. The effect of organic carbon, temperature,time, and redox conditions on soil color. Soil Science 150: 506-512.FAO. 1998. World reference base for soil resources, World Soil Resources Reports 84. Rome: Foodand Agriculture Organization of the United Nations.Fujihara Industry Co. 1970. Revised standard soil color charts. Tokyo: Fujihara Industry Company.——. 2001. Revised standard soil color charts. Tokyo: Fujihara Industry Company.Melville, M. D., and G. Atkinson. 1985. Soil color: Its measurements and its designation in models ofuniform color space. Journal of soil Science 36: 495-512.Munsell Color Co. 1975. Munsell soil color charts. Baltimore: Munsell Color Company.——. 2000. Munsell soil color charts. Baltimore: Munsell Color Company.Sève, R. 1991. New formula for the computation of CIE 1976 hue difference. Color Research andApplication 16: 217-218.Soil Survey Staff. 1993. Soil survey manual, Handbook 18. Washington: US Government PrintingOffice.——. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soilsurveys, Handbook 436. Washington: US Government Printing Office.Address: Manuel Sánchez Marañón, Departamento de EdafologíaFacultad de Ciencias, Universidad de Granada, 18071 Granada, SpainE-mails:154